Wallow Fire out, but flooding and erosion dangers remain

by Dennis Wagner - Oct. 16, 2011 12:00 AMThe Arizona Republic

ALPINE - A few days after the Wallow Fire blew up in the White Mountains in May, Chris Nelson began work to save the forest from rain.

Planning for a flood in the midst of flame may seem incongruous. But as a U.S. Forest Service expert on wildfire rehabilitation, Nelson knew that erosion caused by Arizona's summer storms would pose a threat nearly as great as the billowing inferno.

"The biggest concerns from a wildfire are the flooding and the loss of soil afterward when the monsoons hit," said Nelson, watershed program manager for the Apache-Sitgreaves National Forests.

While flames consumed the backcountry, Nelson and other scientists raced to prevent the kind of secondary destruction that would harm the forest even further.

Higher-than-normal precipitation was forecast within a few weeks, possibly the most rain in 25 years. Absent a military-efficient response, Nelson said, the scorched forest floor might wash away in mudslides, tearing up roads, inundating communities. After the 2010 Schultz Fire, which was a fraction of the size of the Wallow, flash flooding swamped dozens of homes near Flagstaff and caused the drowning of a 12-year-old girl.

Once critical topsoil is washed away, grasses, trees and other plants struggle to grow back. When habitat is damaged, wildlife stays away.

The Forest Service's answer to that threat is a program known as Burned Area Emergency Response, or BAER. It is designed to protect lives, property and cultural resources such as artifacts and petroglyphs in fire-ravaged woods by removing trees that may topple and other public-safety hazards, as well as stabilizing soils and salvaging burned trees.

As the Wallow Fire raced north toward Springerville and spread east toward New Mexico, an army of 200 scientists and laborers moved into the still-smoldering burn zones around Alpine, Eagar, Greer and other communities jeopardized just days earlier.

The job was enormous.

The blaze burned for 41 days, torched 841 square miles and destroyed an estimated 16 million mature Ponderosa pines over an area double the size of Phoenix.

Based on infrared satellite images and field analyses, Forest Service experts mapped out the devastation:

- Soils covering 16 percent of the fire area suffered severe damage. High winds, steep topography and thick fuel supplies generated firestorms so intense that all plants were incinerated from roots to crowns. An additional 14 percent of the land sustained a moderate burn, with half to three-quarters of the trees killed.

- Even in piney woods at higher elevations, where wildfire typically hugs the ground, flames raced through crowns, causing an unusual kill rate.

In those areas, fire temperatures up to 1,200 degrees chemically sealed an underground earthen layer, making it "hydrophobic" - unable to absorb water.

As the flames subsided, the summer storms loomed. Tom Tidwell, the Forest Service chief, recognized an urgent threat, promising money and manpower.

"The response to this fire," he said in a news release, "must be immediate and sustained."

Priority areas targeted

Scientists and work crews swarmed over the charred forest.

The Wallow Fire, which authorities say was started by careless campers, destroyed 38 structures as it became the largest forest blaze in recorded Arizona history.

Foresters knew they had to lay down a protective layer of grass seed and mulch within weeks, hoping that early light rains would allow roots to take hold, anchoring the soil. With a limited budget, the priority targets were intensely burned areas near towns, along steep slopes and close to streams.

Soil scientists and hydrologists moved in to determine what treatments would be required and where.

Fisheries managers and wildlife specialists studied the impact on a wounded ecosystem.

Engineers and construction crews began work to protect roads, bridges, campgrounds and towns from flooding. Contractors started cutting hazardous trees along 300 miles of roadways and 38 miles of power lines.

Work teams from state prisons and a nearby Apache reservation cleared debris from streambeds and drainage channels.

Logging companies began contemplating a salvage harvest of as many burned trees as possible.

Most critically, helicopters started bombarding the forest. Over several weeks, they applied 34,000 tons of hay mulch - 4,500 truckloads - at a cost of $19 million.

They also seeded 84,000 acres with wheat, barley, blue gamma, Arizona fescue and other grasses under contracts that paid out $6 million.

Then the thunderheads appeared.

Nelson recalls hoping for enough moisture to germinate the seeds yet worrying about an inundation. His mantra: "The good thing is, we've got rain. And the bad thing is, we've got rain."

Outside the national-forest boundaries, local communities walled themselves with sandbags in preparation for flooding.

By September, 8 inches of rain had fallen on the burn zone, about 2 inches above normal.

Some streams and washes overflowed, spilling into communities and undermining roads. A house in Nutrioso was destroyed by the crushing flow of soil, ash and tree limbs. A motel, the ranger station and other businesses in Alpine were hit with minor flooding.

But for the most part, weather cooperated and topsoil held.

"The good news is, the seeding they put in has taken root, and it's knee high," said Bill Greenwood, town manager in Eagar. "We're cautiously optimistic that we dodged a bullet."

The government, which poured $109 million into fighting the blaze, is spending an additional $34 million on the emergency rehab effort.

Erosion still a threat

Early this month, Rick Davalos, a ranger in the Alpine Ranger District, wheeled his pickup truck past a thicket of blackened, branchless, yet still-standing tree trunks.

So many pine boughs were obliterated, he said, that cellphone coverage has improved throughout the woods.

He stopped in a deep vale where the Wallow Fire did its worst and where researchers are studying the value of seeding and mulching.

Scientists from the Forest Service's Rocky Mountain Research Station have planted patches of grass on the burned slopes. They are measuring the soil slough below, as well as sediment volumes flowing into a tiny stream.

Within the scientific community, there is some controversy about whether seeding a charred forest really stops erosion and whether exotic grasses and weeds may inhibit the return of indigenous plants.

Nelson said the non-native annuals are replaced by native species within a couple of years and - at least in Arizona's forest - there is no question that they protect the earth. He points out seeded and mulched slopes, where a verdant carpet covers the forest soil. Nearby, where no seeds were dropped on areas less severely burned, the ground remains a naked brown with signs of sloughing.

With thousands of acres still untreated and the entire countryside damaged, Nelson said the erosion threat will persist through spring snowmelt and beyond: "We'll have an emergency here for years and years."

And some parts of the forest may not recover for generations: A Ponderosa pine grows 12 to 18 inches annually, not reaching the adult height of 80 feet for a half-century or more.

In the worst burn areas, conservationist Bryan Bird says, "We will not see mature forests there again for hundreds of years."

Restoration taking hold

For high-country residents, the damage is done.

Where cabins were saved, views are wrecked.

Tourism, the lifeblood of mountain towns, was wiped out through much of the summer and is only beginning to revive. Campgrounds are closed, along with 300 miles of hiking trails.

The Wallow Fire legacy includes 514 miles of alpine streams filled with ashen sludge that likely killed off Apache trout and other fish.

Ranchers, who were forced to evacuate cattle, may not be able to return for more than a year because the soil remains so fragile. Flames damaged more than 500 miles of fencing and ruined dozens of stock ponds and springs.

Wildlife specialists are still studying the impact on threatened species such as the Chiricahua leopard frog and the gray wolf. More than half of the old-growth nesting areas for 76 Mexican spotted owls went up in smoke.

Still, Nelson and other experts said, over the long haul, the Wallow Fire will be seen as having done a lot of good.

Decades of misguided fire suppression had created an excess of brush and thin, unhealthy trees that made the forest vulnerable to destructive blazes. Now that the fuel is gone, lightning-caused fires can move safely and naturally along the forest floor.

"At least half the Wallow Fire, we would have burned it that way if we were going to treat it," Nelson said. "We won't have the running crown fires here now, and it opens up the potential for more controlled burning to keep the forest healthy."

Bird, wild-places program director for the WildEarth Guardians conservation group, agreed that the Wallow Fire was partly beneficial, even if it killed off an unusually high percentage of pines.

"These are big, scary events when they're burning, and you see 20,000-foot smoke plumes and people are running for their lives or losing their homes," Bird said. "But, generally speaking, it was not as bad as we thought."

Nelson said about 90 percent of the rehabilitation work is done.

Molly Pitts of Eagar, who is executive director of Northern Arizona Wood Products Association and vice chairwoman of the Governor's Forest Health Council, said the BAER rehab program "did what it's supposed to do," though she would like to see a streamlined program for long-term logging of trees killed by the fire.

At the Apache County Sheriff's Office, Sgt. Richard Guinn said local residents protected themselves using thousands of sandbags to divert runoff, while the BAER team did a good job of preventing erosion. "Once they started getting the hay down, we saw a reduction in flows," he added. "Given what they were working with, I think they did what they could."

Deer, bears, squirrels and other wildlife, which returned to the burn zone within days, now forage in meadows more lush than before the blaze. "They're all going to go on a real upswing in the next few years," Davalos predicted.

Even hunters are back, roaming the backcountry in search of deer and elk.

Although the Wallow Fire was a worst-case scenario, Nelson said, the restoration campaign is a success so far: "I would give it an 'A.' . . . I've never seen anything happen this fast."

Vada Davis, owner of the Bear Wallow Cafe in Alpine, said she drives nearly 30 miles through the forest each day from her home in Eagar. "I think it's beautiful," she said. "You look at the green grass and the black trees and the yellow flowers. I'm not glad it burned, but it's really pretty."